Cameron has told me in the past that he is not passionate about producing.

“Well, yeah, then Guillermo came along,” he says. “In this particular case, I’m working with Guillermo because I enjoy his company, and a creative collaboration is something that we’ve talked about doing for a long time.”

“It’s going to be an epically scaled horror film and we haven’t seen anything like that in a really long time — I guess since Aliens.”

Like the novella on which it’s based, the film will take place in the Antarctic, where humans encounter a race called the Ancient Ones. “The thing about Lovecraft is that he left a lot to the imagination,” Cameron says. “He never told you what they looked like. He managed to create a sense of creeping horror without specifics.”

“Guillermo brings an eye for design that is so original and so quirky and so steeped in the lore of movie design and horror design, but always fresh and unexpected. Frankly, I just want to see what he comes up with and I want to enable the nuts and bolts of the production so he doesn’t have to worry about that. I want to help him work in 3-D.”

Guillermo del Toro has been wanting to make At The Mountains Of Madness for years and he was in talks with Warner Bros. to adapt it in 2006, but according to Toro they were “very nervous about the cost and it not having a love story or a happy ending”. However the combination of del Toro and Cameron spurred Universal to hand over the money and the last we heard the studio and del Toro are intending to begin pre-production soon ready for a summer 2011 shoot.

Shargraves

hmmmm. Has Camroon never read it? The Elder things are described in bewildering detail –

Six feet end to end, three and five-tenths feet central diameter, tapering to one foot at each end. Like a barrel with five bulging ridges in place of staves. Lateral breakages, as of thinnish stalks, are at equator in middle of these ridges. In furrows between ridges are curious growths – combs or wings that fold up and spread out like fans. . . which gives almost seven-foot wing spread. Arrangement reminds one of certain monsters of primal myth, especially fabled Elder Things in [the] Necronomicon.
—H.P. Lovecraft, At the Mountains of Madness

Of course Guilermo knows the description of Elder Things from Lovecraft literature!!! In Hellboy 2, the Elder Things make cameo appearances:
first in the BPRD headquarters and next in the Troll Market.
Chk it out! They look as close to literature as you can get!